Technical Field
Aspects of the present disclosure relate to a PZT-film laminated structure, a liquid discharge head, a liquid discharge device, a liquid discharge apparatus, and a method of making the PZT-film laminated structure.
Related Art
Recent years, piezoelectric actuators have been increasingly used. As piezoelectric ceramics used as actuator, for example, composite oxides are known that have perovskite crystal structures and can be represented by a chemical formula, ABO3. Among the composite oxides, as a material most generally used for many years, for example, lead zirconate titanate (PZT) is widely known in which lead (Pb) is applied to A and a mixture material of zirconium (Zr) and titan (Ti) is applied o B of the chemical formula, ABO3.
As a method of producing the PZT film, for example, a thick-film method of PZT using green sheet, a sol-gel (SG) method, and a sputtering method are known. In the thick-film method, PZT powder is used as raw material. In the sol-gel method, an organic material containing liquid metal is used as raw material. The organic material is coated on a substrate by, for example, spin coating, spraying, or roll coating to form a film on the substrate, and baked to form a coating film. In the sputtering method, using a ceramic sintered body acting as a target having a predetermined composition, Ar gas or sputtering gas, in which O2 is added to Ar gas, in plasma state is impinged to the target to deposit a piezoelectric film on a substrate. According to the production methods as described above, the PZT film is produced.
However, in each of the production methods, impurities of raw materials are considered to act as disturbance factors to the target functions of the materials. Hence, there is demand for a technique to obtain a PZT film that has a preferable crystal orientation even when produced by, for example, the sol-gel method and achieves a great amount of displacement when used as actuator, regardless of the method of producing the PZT film.